Area Forecast Discussion
Issued by NWS Charleston, WV

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000 FXUS61 KRLX 181810 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 210 PM EDT Wed Oct 18 2017 .SYNOPSIS... Dry high pressure with cool mornings and warm afternoons, with temperatures moderating through the weekend. A strong cold front and low pressure system cross early next week. && .NEAR TERM /THROUGH THURSDAY/...
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As of 140 PM Wednesday... A s/w trof will cross the area overnight with little fanfare. What it will do is keep the boundary layer winds up so that any frost should be patchy in nature and confined to the most protected hollows in the northern lowlands. This will also serve to mitigate dense river valley fog, save for the mountain valleys. Lows tonight were primarily derived from a met/mav blend except across the mountain valleys/northern lowlands, where forecast lows are a bit below guidance. Thursday will be another stellar day after a cool start. Afternoon temps will average 5 to 8 degrees above normal.
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&& .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... As of 420 AM Wednesday... High pressure and upper level ridging cross this period, bringing about dry, pleasant mid autumn weather. Central guidance temperatures reflect a warming trend in increasing southerly flow, around the back side of the exiting high. Lowered afternoon dew points a bit. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 420 AM Wednesday... Pattern amplification takes place this period, with deep troughing developing in the east, and an equally amped up ridge in the west. After one more dry, warm day on Sunday, an initial upper level northern stream trough drives a cold front toward the area Sunday night, bringing an increasing chance for showers overnight Sunday night and Monday. A second upper level short wave trough digs deep into the eastern U.S. Monday night through Tuesday night, carving out a deep long wave trough by Wednesday. This drives a cold front through the area Monday night and Tuesday. This timing can vary, with the front possibly pushing into the Ohio Valley as early as Sunday night, on account of the initial northern stream short wave trough. Also, whether and when the second, digging trough picks up a southern stream feature, will determine whether and when a surface wave comes up along the front in the Monday night-Tuesday night period. With high confidence in trough amplification, and moderate confidence on a wave moving up along the front as the front crosses, have likely PoPs Monday and Monday night into Tuesday. Also have the chance for afternoon thunder ahead of the could front, throughout the area on Monday, and eastern portions of the area Tuesday. The northward transfer of moisture by the southern stream wave coming out of the Gulf of Mexico, will enhance precipitation amounts, if it comes up before the front is driven clear east of the area. The chance for showers continues Wednesday, beneath the low upper level heights. Central guidance temperatures reflect a cooling trend in response to the amplification of the trough in the eastern U.S., with highs below normal by Wednesday. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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As of 205 PM Wednesday... S/W trof swings thru overnight which will keep the boundary layer mixed to an extent. This, in turn, should mitigate dense river valley fog. As such the tafs were kept void of IFR or worse fog overnight except at KEKN, where a strong low level inversion will stiff arm the puff at H925. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z THURSDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Dense fog may affect more terminals if low level winds relax. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H H H M HTS CONSISTENCY H H H H H H H H H H H M BKW CONSISTENCY H H H H H H H H H H H M EKN CONSISTENCY H H H H H H H H H H M L PKB CONSISTENCY H H H H H H H H H H H M CKB CONSISTENCY H H H H H H H H H H H M AFTER 18Z THURSDAY... Dense valley fog possible each morning through the weekend, and in rain at times early next week.
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&& .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...ARJ/30 NEAR TERM...30 SHORT TERM...TRM LONG TERM...TRM AVIATION...30 is the U.S. government's official web portal to all federal, state and local government web resources and services.